Colchicine after-effects on the absorption and utilisation of sucrose by Cunninghamella sp.

Summary

Colchicine had no significant effects on the rate of growth of Cunninghamella when administered in 5 p.p.m. concentration; at 10 p.p.m., it induced a slight increase, while at higher concentrations it lowered the dry weight. Pretreatment with colchicine, during the fungal growth induced a persistant activation of hexose phosphorylases, particularly fructose phosphorylase; more promenantly by the continuous supply of the drug than during the recovery on Richard's medium; a phenomenon that might be partially or wholly alleviated by transfer of the treated mats to Richard's solution alone. In all cases the CO₂ output of the treated samples was unaffected by the drug except at higher levels (20 p.p.m.).

Colchicine treatment favoured the accumulation of polysaccharides; the rate of accumulation depended entirely on both the dose and duration of administration. Furthermore, lower concentrations of the drug favoured nucleoprotein formation but had no effect on nucleotides while the higher concentrations reduced both fractions: a phenomenon that persisted whether the tissues were continuously fed with the drug or recovering on nutrient solution alone.

The changes in the metabolic pathways of the absorbed sugars have been thoroughly discussed.